Medical catheters are used for innumerable minimally invasive medical procedures. Catheters may be used for delivery of therapeutic drug doses to target tissue and/or for delivery of medical devices such as lumen-reinforcing or drug-eluting stents. Likewise, catheters may be used to guide medical instruments to a target site to perform a surgical procedure, such as tissue rescission, ablation of obstructive deposits or myocardial revascularization.
Myocardial injection devices may be used to deliver therapeutics to the myocardial wall to stimulate myocardial angiogenesis and myocardial tissue regeneration. Unfortunately, not all patients have ventricular walls of equal thickness, which makes it difficult to treat those patients with thin ventricular walls with a needle having a single depth. For example, if the depth of injection of the needle causes the needle tip to extend through the ventricular wall, the therapeutic will not be delivered to the desired location, and thus the effectiveness of the procedure will be compromised. Similarly, there is a wide range of wall thicknesses even within a single patient's heart, which requires multiple needles, each with a different depth of injection. In addition, large tissue areas may also need to be treated that would require numerous injections be delivered by the needle to cover the entire area. To do this, the needle would have to be positioned over and inserted into each injection site, which is time consuming and does not lend itself to an even or organized pattern of delivery of the therapeutic agent. As a result, procedural times and costs are increased due to using and switching between multiple needles and/or having to move the needle to and inject into multiple positions within the target tissue area.